I played for years with a guy who built his career around "sit ins". His name is Preston Weber. I played two sets on B-3 and Rhodes, and backed him on a double-kneck Carvin bass/6 string combination the other two sets. When it came time to solo, I switched to pedal bass.

The guy was awful! He couldn't tune his guitar, never rehearsed once in 10 years, was always late, didn't know the words to songs, had bad timing, and was the highest paid guy in the area. He created a party, and half the audience was there to sing, play the "gut bucket" or tamborine...whatever. Most knew one or two songs. All were terrible. But, they would bring their friends and wait for hours to be called upon. It was terrible music, but what a party. Preston leveraged egos into a lifetime career. The rooms he played were packed six nights a week. He played the cheeziest selection of sing-along type songs you ever heard. He started off as a folk singer and switched to primarily country songs when the timing was right. I made 1/3 the money he made and played twice as long.
From a business and entertainment standpoint he was worth every penny. This made me appreciate the ability to entertain (something I'm not good at).
I just sat back an laughed my a** off!

Russ